Charles K. Kao was named one of three winners of the Nobel Prize in Physics 2009 “for groundbreaking achievements concerning the transmission of light in fibers for optical communication.” Kao won one-half of the 2009 Prize for his discovery of how to transmit light signals over long distances through glass fibers as thin as a human hair. His 1966 breakthrough led to the creation of modern fiber-optic communication networks that carry voice, video and high-speed Internet data around the world.

As detailed in the Nobel Committee scientific information, “An intense search for suitable transmission media in the optical domain began at the beginning of the 1960s. The optical fiber was, however, mostly set aside because of its high attenuation…The attenuation of the first optical fibers was typically 1000 dB/km, implying that only 1% of light got transmitted in twenty meters of fiber.”

“…Charles K. Kao was a young engineer at Standard Telecommunications Laboratories (ITT) working on optical communication. He started under the direction of Karbowiak, and then became in charge of a small group…They investigated in detail the fundamental properties of optical fibers with respect to optical communication. In particular, they did not consider the physics of waveguides only…but also the material properties. Their conclusions were presented by Kao in London in the beginning of 1966…”

“The most important result was that losses in dielectric media were mostly caused by absorption and scattering. The predicted attenuation of a few dB/km was found to be much less than that measured at the time. Consequently, the latter was predominantly caused by impurities, in particular iron ions. Fibers with glass of higher purity could be a good candidate for optical communication. Damping caused by bending and waveguide imperfections, as well as propagation and radiation losses were also analyzed and found to be small. Single mode fibers were presented as the best transmission medium for optical communication.”

“What the wheel did for transport, the optical fiber did for telecommunications,” said Richard Epworth, who worked with Kao at Standard Telecommunications Laboratories in Harlow, England in the 1960s. “Optical fiber enables you to transmit information with little energy over long distances and to transmit information at very high rates.”